Pesq. Vet. Bras. 26(2):102-104, abr./jun. 2006
Seroprevalence of L eptospira spp in cattle from Monte Negro
municipality
municipality,, western Amazon1
Daniel M. Aguiar2*, Solange M. Gennari2, Guacyara T. Cavalcante2, Marcelo B.
Labruna2, Silvio A. Vasconcellos2, Aline A. R. Rodrigues 3, Zenaide M. Moraes2
and Luis M.A. Camargo4
ABSTRACT
.- Aguiar D.M, Gennari S.M., Cavalcante G.T., Labruna M.B., Vasconcellos S.A., Rodrigues
ABSTRACT.A.A.R., Moraes Z.M. & Camargo L.M.A. 2006. Seroprevalence of Leptospira spp in cattle from
Monte Negro municipality
municipality,, western Amazon. Pesquisa Veterinária Brasileira 26(2):102-104.
Department of Preventive Veterinary Medicine and Animal Health, Faculty of Veterinary Medicine
and Animal Production, University of São Paulo, Av. Prof. Orlando Marques de Paiva 87, São Paulo,
SP 05508-900, Brazil. E-mail: [email protected]
The prevalence of anti-Leptospira spp antibodies was investigated in 2,109 female cattle from 86
herds of Monte Negro municipality, Rondônia, Brazil. Sera samples were evaluated by Microscopic
Agglutination Test against 24 leptospira serovars. Titers =100 for at least one of 24 leptospira
serovars were detected in 1,114 cows (52.8%) from 82 (95.3%) herds. The adjusted overall prevalence
for Monte Negro municipality was 53.9% (49-58.7%; CI: 95%). The most prevalent serovars were
Hardjo (14.5%), Wolffi (12.3%), Shermani (10.8%), Patoc (7.9%), and Hebdomadis (6.1%). Other serovars
worldwidely reported like Bratislava, Pomona and Grippotyphosa were detected in low levels.
INDEX TERMS: Leptospira spp, cattle, epidemiology, Amazon.
INTRODUCTION
RESUMO
.- [P
P revalência de anticorpos antiRESUMO.anti-LL eptospira spp em
bovinos do município de Monte Negro, Amazônia Ocidental
tal.] Foi investigada a prevalência de anticorpos anti-Leptospira
spp em 2.109 vacas provenientes de 86 rebanhos do município
de Monte Negro, Rondônia, Brasil. As amostras de soro sanguíneo foram avaliadas pelo Teste de Aglutinação Microscópica frente a 24 sorovares de leptospira. Títulos =100 para um ou mais
sorovares foram detectados em 1.114 vacas (52,8%) de 82 (95,3%)
rebanhos. A prevalência ajustada para o município de Monte
Negro foi de 53,9% (I.C.: 95%; 49-58,7%). Os sorovares mais
prevalentes foram Hardjo (14,5%), Wolffi (12,3%), Shermani
(10,8%), Patoc (7,9%) e Hebdomadis (6.1%). Outros sorovares
mundialmente relatados como Bratislava, Pomona e
Grippotyphosa foram pouco detectados.
Leptospirosis infection has been reported as a cause of economic
losses on beef and dairy cattle. Infected herds present
reproductive failures as abortion, infertility, sterility, stillbirth or
weak calves and agalactia. Furthermore, it is one of the most
important zoonoses in the world (Radostits et al. 2000).
Additionally, leptospirosis is found worldwidely and its
seroprevalence could be different according to herds, areas,
and countries. Water is the main vehicle for spreading the agent
in the environment, making tropical highly suitable for
maintenance of Leptospira serovars (Radostits et al. 2000).
The Brazilian Amazon region, the largest forest biome of the
world, is a new frontier where agricultural development and
livestock activities have been attempted. The state of Rondônia
is a developing area in the western Amazon of Brazil, where very
few information about the occurrence of leptospirosis in cattle
herds have been reported (Homem et al. 2000). The present
study evaluated the prevalence of anti-Leptospira spp antibodies
in cattle, from Monte Negro municipality, Rondônia.
TERMOS DE INDEXAÇÃO: Leptospira spp, bovinos, epidemiologia,
Amazônia.
1
Received on August 10, 2005.
Accepted for publication on October 23, 2005.
2 Department of Preventive Veterinary Medicine and Animal Health, Faculty
of Veterinary Medicine and Animal Production, University of São Paulo
(USP), Av. Prof. Orlando Marques de Paiva, 87, São Paulo, SP 05508-900,
Brazil. * Author for correspondence. E-mail: [email protected]
3 Department of Animal Reproduction, FMV, USP, São Paulo, SP.
4 Biomedical Science Institute, USP, Campus Monte Negro, RO.
MA
TERIALS AND METHODS
MATERIALS
In late 2001, Monte Negro municipality (10o 15' 35"S, 63o 18' 06"W)
722 herds) comprising 116,736 bovines. Nelore
had 722 cattle farms (722
was the predominant beef breed whereas dairy cattle were crossbred
of zebu and several European breeds. The region has a hot and wet
102
Seroprevalence of Leptospira spp in cattle from Monte Negro municipality, western Amazon
climate, with high levels of precipitation that achieve 2,000mm
annually, with a moderate drought period from April to September.
Temperature ranges from 25 to 29oC and the relative humidity from
70% to 80% throughout the year. In this region, cattle are not vaccinated
against leptospirosis.
The number of farms to be investigated in the present was
calculated by EpiInfo 6.04 with 50% of estimated prevalence, 10% of
absolute precision desired, and 95% of confidence interval. Then the
minimum number of farms obtained was 86. Each farm represented
one herd. The number of cows tested on each farm was calculated
with 95% confidence of detecting at least one seropositive animal per
farm with at least 5% of seropositive cows in the herd (Thrusfield
1995).
Serum samples from the 86 farms were collected from May to
October 2002 and stored at -20o C. The farm sample was composed of
11 beef, 50 dairy and 25 mixed cattle herds. Serum samples were
analyzed by Microscopic Agglutination Test (MAT; Galton et al. 1965,
Cole Junior et al. 1973) with the cut off 1:100 dilution against 24
leptospira serovars (Andamana, Australis, Autumnalis, Bataviae,
Bratislava, Butembo, Canicola, Castellonis, Cinoptery, Copennhageni,
Grippotyphosa, Hardjo, Hebdomadis, Icterohaemorrhagiae, Javanica,
Panama, Pomona, Patoc, Pyrogenes, Sentot, Shermani, Tarassovi,
Wolffi and Whitcombi) cultivated in modified EMJH medium (Alves et
al. 1996). Positive sera were retested against each reactant serovar in
two fold serial dilutions. The serum titer was the reciprocal of the
highest serum dilution that presented 50% of agglutination. The most
probable serovar was the one that presented the highest titer. When
one animal presented the same highest titer for two or more serovars
it was not included in the analyses of the most probable serovar.
Prevalence of leptospirosis was calculated by herd and by animals.
As we evaluated herds with different sizes, the overall prevalence
was adjusted by herd size (Thrusfield 1995). Animal prevalence values
were also determined separately for herds allocated in each of the
three different kinds of management: dairy, beef or mixed herds.
Prevalence values among beef, dairy and mixed herds were compared
by the Chi-Square test (c2). These calculations were generated by
using the Epiinfo 6.04 program.
RESUL
TS
RESULTS
Serum samples were collected from 2,109 cows from 86 farms,
being 584 from beef, 1,011 from dairy, and 514 from mixed
herds. At least one seropositive animal was detected in each of
82 herds, giving a herd prevalence of 95.3% (88.5-98.7%; CI:
95%). A total of 1,114 cows (52.8%) presented antibodies against
one or more serovar studied (Table 1). The adjusted overall
prevalence of Leptospira spp seropositive cows for Monte Negro
municipality was 53.9% (49-58.7%; CI: 95%).
Table 1. Serological results of antianti-LL eptospira spp antibodies
among cattle from 86 herds of the rural area of Monte Negro
municipality
ondonia, Brazilian western Amazon
municipality,, R
Rondonia,
Production
Beef
Dairy
Mixed
Total
Leptospira spp antibodies
Herd
Animal
Positive Examined %*
Positive Examined
11
47
24
82
11
50
25
86
100.0 b
94.0 b
96.0 b
95.3
364
482
268
1,114
* Different letters in the same column: P<0.05.
584
1,011
514
2,109
%*
58.7 a
49.6 b
52.3 b
52.8
103
Table 2. Animal and herd seroprevalence according to
different Leptospira serovars among cattle from Monte Negro
municipality
ondonia, Brazilian western Amazon
municipality,, R
Rondonia,
Leptospira serovar
Positive animal
Number
%
Hardjo
Wolffi
Shermani
Patoc
Hebdomadis
Bratislava
Autumnalis
Pyrogenes
Castellonis
Canicola
Pomona
Australis
Butembo
Whitcombi
Grippotyphosa
Icterohaemorrhagiae
Copennhageni
Not characterized reaction*
162
137
120
88
68
44
31
22
17
16
14
11
10
06
04
04
04
356
14.5
12.3
10.8
7.9
6.1
3.9
2.8
2.0
1.5
1.4
1.3
1.0
0.9
0.6
0.4
0.4
0.4
31.8
Positive herd
Number
%
37
47
49
43
28
25
23
16
14
12
12
09
08
05
04
04
03
02
45.0
57.3
60.0
52.4
34.1
30.5
28.0
19.5
17.0
14.6
14.6
10.9
9.7
6.1
4.9
4.9
3.6
2.4
* Identical highest titer for two or more serovars.
A total of 32% (n = 356) of the seropositive cows had
antibodies against more than one serovar studied, without most
probable characterization. The serovars Hardjo, Wolffi and
Shermani were detected as the more prevalent. Each serovar
reported in the present study with result by animals and herds
are summarized in Table 2.
DISCUSSION
The present study shows a herd prevalence of 95.3% for Leptospira
infection, which is similar to the value of 97% reported in another
study conducted in the State of Pará, eastern Brazilian Amazon
(Homem et al. 2000). In contrast, in a similar study in Spain,
Alonso-Andicoberry et al. (2001) reported 42.8% of herds with
leptospirosis. These differences between Brazil and Spain could
be explained by the climatic diversity of the related areas, since
in the tropical wet areas the survival of Leptospira serovars in the
environment could be longer than in other non-tropical areas
(Radostits et al. 2000).
In the present study, prevalence by animal was estimated to
be 53.9%, which is similar to another study conducted in the
Amazon region of Brazil (State of Pará) which detected 66.2% of
seropositive cattle (Negrão et al. 1999). The proportion of
seropositive cattle was significantly higher (P<0.05) for beef
cattle (58.7%) than in dairy (49.6%) and mixed herds (52.3%). These
results agree with Miller et al. (1991) in the USA and Vasconcellos
et al. (1997) in Brazil.
The most-prevalent serovar by animal in the investigated area
was Hardjo. Studies conducted in other regions of Brazil found
similar results (Brod et al. 1994, Lilenbaum & Santos 1996,
Vasconcellos et al. 1997, Ribeiro et al. 2000). Serovar Hardjo is
usually the most-prevalent in cattle worldwidely and is considered
the most adapted to cattle (Radostits et al. 2000).
Shermani was the most prevalent serovar among the 86 herds
of the present study. There is little information about this serovar
Pesq. Vet. Bras. 26(2):102-104, abr./jun. 2006
104
Daniel M. Aguiar et al.
in domesticated animals. It is known that Shermani is maintained
by wild rodents and has frequently been found in serological
studies in the northern area of Brazil (Negrão et al. 1999, Homem et al. 2000). The second most prevalent serovar in animals
and herds was Wolffi. Probably, as Wolffi and Hardjo serovars
belong to the same serogroup (Sejroe); this result could be
assumed as cross-reactions (Faine, 1982). Patoc was the fourth
and third most prevalent serovar by animals and herds
respectively. This serovar has been reported only once in Brazil
(Negrão et al. 1999). This serovar belongs to the Leptospira biflexa
group and is frequently used in serological investigations as
genus specific antigen, due to its cross-reactions with pathogenic
serovars that could be detected earlier in the infection course by
pathogenic serovar (Mauermann et al. 1993). Other serovars
worldwidely reported like Bratislava, Pomona and Grippotyphosa
occurred at low frequencies. Nevertheless, these serovars have
been frequently found in southeastern, midwestern and
northeastern Brazil (Vasconcellos et al. 1997, Negrão et al. 1999,
Ribeiro et al. 1999, Langoni et al. 2000).
The present study showed the relevance of Leptospira spp
infection among cattle in the Brazilian Amazon, with emphasis
on the serovars Hardjo and Shermani.
Acknowledgements.- We are grateful to Dr. F. Ferreira (Faculty of Veterinary
Medicine, São Paulo University); to T. Bronhal and to the Agency of Animal
Sanitary Defense of the State of Rondônia. This work was supported by the
Fapesp. D.M. Aguiar, S.M. Gennari and S.A. Vasconcellos are in receipt of a
scholarship from CNPq and G.T. Cavalcante from Capes.
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